In producing different kinds of sintered products simultaneously, one way to improve the productivity is to connect a compacting step to be carried out before heating, with a heating (sintering) step. Specific ways to make such a connection include 1) coupling one compacting machine with one sintering furnace via a chute, 2) loading parts (hereinafter referred to as works) on a work carrier means (such as a mesh belt) in a continuous heating device such as a mesh belt type furnace, keeping sufficient spaces between different types of works, or 3) putting different kinds of works together on a single tray, supplying the tray into a sintering furnace, and sorting them manually after heat-treatment.
The method 1) requires the same number of sintering furnaces as tile number of types of works to be heat-treated and thus is costly. Also, since the works have to be fed directly into the sintering furnaces one by one, it is difficult to automate the mechanism for taking the works out of the furnaces and thus to feed the works efficiently to the subsequent steps.
In the method 2), works are fed, keeping the spaces for sorting between different types. This will lower the energy efficiency of the heating device. Also, lightweight or unstable works may move on the carrier means and mix into a group of works of a different kind.
The method 3), in which different kinds of works are placed in a single tray and processed in a batch, includes the manual sorting step, Thus, sorting errors are unavoidable and the working efficiency is no good.
A chief object of this invention is to solve these problems.
In an arrangement where a single heating device is used for producing different kinds of works, there may arise an imbalance between the throughput capacity of the heating device and that of the front and/or rear step. Heretofore, it was necessary to stop the front and/or rear step until such an imbalance disappears. This lowers the working efficiency of the apparatus. Another problem of conventional apparatuses is that the conveyors and chutes connecting the adjacent steps tend to interfere with the work operation and thus lower the working efficiency.
A second object of this invention is to solve these problems.